“We’d drink whiskey in the parking lot,” Grohl told Rolling Stone as he explained that Timberlake had dropped by the Foos’ studio and liked what he’d heard. “He was really, really cool. Then the night before his last day he said, ‘Can I sing on your record?’ I don’t want to push it, but I just want to be able to tell my friends.’” The result is a series of wordless background vocals added to one track, which the bandleader last month described as a “dirty little secret” and he’d be interested to “see if anyone can figure it out.” (Again, we did).

While Grohl didn’t come right out and say Timberlake was the mystery guest, a second Rolling Stone story confirmed Timberlake was indeed the artist to whom they previously referred.

He went on to reveal that he’d brought McCartney on board by texting the message, “Do you want to play drums on one of our new songs?” to which the former Beatle replied, “You’re crazy, man!” Grohl said, “It’s inspiring because he’s still playing for the same reasons we all started playing when we were young – he just wants to jam.”

Grohl recently pointed out that Concrete and Gold carries some of his most political lyrics to date, but said in the new interview, “When the Foo Fighters go out and tour, we play to everyone. I like to think that music is something that can bring two opposite sides to the spectrum into the same area for three hours of relief. There’s a part of me that thinks I’m better at giving people hope. So that’s where I’d rather be.”